During arthroscopic surgery there is a well established need for cannulae for a wide variety of procedures. These include, but are not limited to procedures in all of the joints treated by arthroscopic techniques. To meet this need, there are a number of cannulae available with a number of differing designs to control fluid flow, prevent slippage of the cannula and allow passage of instruments, sutures, implants, anchors or fiber-optic devices to and from the site of the procedure. In the past a design feature with expandable wings that engage the subcutaneous tissues to help hold the cannula in place has been developed. Unfortunately these wings are often larger than the space available in various locations of the body, such as joints and are not suited to be used in small spaces in the body. These prior art devices cannot accommodate the shape of the individual joint spaces. Further, these prior art mechanisms require a recess from the tip of the cannula, or a weakness of the attachment for its functionality, such as described in U.S. Pat. No. 6,325,812, issued to Dubrul. Furthermore, the mechanical design of the hinged flaps of the prior art devices cannot be shortened or changed at the time of surgery by the surgeon to accommodate the shape of the joint or to directly aid in exposing the surgical sight of interest.
More importantly there is a current need, well known to those familiar in the advanced form of the art, for internal retraction of the soft tissue allow for a reduction of the fluid pressures required to distend or open the joint space. Such a system would allow for longer operative times and therefore allow more sophisticated and complex procedures to be completed using less fluid at a lower pressure inside a joint space to distend the joint. This would reduce the need for absolute seals at the ends of the cannula, as well as reduce the complications associated with high pressure fluid pumps as well as the resultant fluid extravasations into the local extra-articular tissues in order to keep the joint or body cavity space open. This would also decrease the risk of skin complications, loss of visualization and nerve damage in the more complex cases requiring longer operative times. The flexible wing design of the present invention would produce customizable soft tissue retractors that would service this purpose. A device with these features would increase safety with longer surgical times or more complex procedures thereby advancing the state of the art. Furthermore, there is a need in the state of the art to have a device of this type with a sufficiently simple design as to allow for inexpensive manufacture or mass production in a multitude of sizes and configurations to accommodate many differing joints or body cavities.
Therefore, with that in mind, there is a need in the current art for a self, holding cannula that could be manufactured in any size, and be customizable at the time of surgery that has the advantages outlined below.